It looked like TEST UNIT READY took 37min to complete! Only after this command finished, the VM reset preparation continued. So what is this mysterious command, and what took it so long to complete?TEST UNIT READY is a SCSI command sent to the target in order to get a response, and a status of the device. In the log file, ide1:0 is referred, but CD-ROM drive in this VM isn’t mounted according to vSphere client –

Just to make sure, I checked out the vmx file, which showed me something I didn’t see from the vSphere client side –

vmx file indicates of an iso mounted to this VM. Not just an iso, but the VMware tools iso. Checking again from the guest OS side – and the disk isn’t mounted. So what just happened here?

On enterprise companies, you might find a vCenter managing few DNS zones (a.serv.corp, b.serv.corp etc.). There might be a situation where there are few vCenters, each manages a different domain. Keeping track on HP iLO* IPs is easier when you register the iLO IP in the DNS, and use “ilo” as a prefix to each server – for example, esx01 iLO address will be ilo-esx01 and so on. It all works until it doesn’t, since host name changes, and maintaining it for more than just a few ESXi hosts can be demanding. Enters PowerShell.

I’ll assume you have some PowerShell / PowerCLI experience, and you know how to add the right snapin, and connect to the relevant vCenter(s).

First, add the Get-VMHostWSManInstance function, with prerequisites described here: